Various types of agricultural implements have been developed that can be linked via an implement tongue assembly to a drawbar of a tractor or other type of tow vehicle to facilitate different tasks, including, for example, seeding, fertilizing and tilling. Hereinafter, unless indicated otherwise, the background of the invention and the present invention will be described in the context of an exemplary planting implement.
An important fact in accessing the value of a planting implement is how quickly the implement can accomplish the task of the implement. The speed in accomplishing the implement's task can be increased by reducing the number of passes required to perform the implement's task for a field. Certain known planting implements are configured to expand to operating field widths of 40-feet or more. Unfortunately, such expansive widths cannot be tolerated during planter transportation, storage, and egress of the implements to and from many agricultural fields. In particular, many farmers use commercial roadways to transport their planting implements to and from the fields, and essentially all roadways are not designed to accommodate expansive planting implements. The industry has developed planting implements that are operable to fold to and from a retracted configuration between transport and intended use.
One certain folding-type planting implement includes a single implement tool bar centrally mounted for pivotal movement on a wheel supported carrier platform where the single arm is pivotable about the mount so that approximately half of the bar extends over the tongue assembly and is a supportable thereby and the other half of the bar extends away from the tractor behind the chassis. The tongue assembly has to be long enough to accommodate the implement bar length plus some clearance so as to allow a tractor linked to the tongue assembly to turn left and right. For example, where the planting implement operating width is 40-feet, the tongue assembly generally has to be greater than 20-feet long.
To ensure planting along the entire edge of a field, a farmer typically starts seeding the field by first traveling around the edge of the field with a seeding implement at lease once and often two or more times along adjacent consecutively smaller paths prior to traveling in parallel rows through field. These field edge paths are generally referred to in the industry as headland passes. Performing one or more headland passes about a field edge prior to performing parallel passes provides a space for turning the tractor an implement around between parallel passes while still covering the entire space along the field edge. However, headland passes increase opportunities for driving over field sections that have already been seeded, crushing passed-over seeds or growing plants and reducing overall field production. As known in the industry, farms routinely attempt to reduce the number of headland passes required in a field.
The number of headland passes required to facilitate field coverage is related to the turning radius of a tractor and planter implement combination, and the turning radius of the combination is directly related to the length of the tongue assembly coupling the planting implement with the tractor. Recognizing that a short tongue assembly during planting operation reduces the number of headland passes and increases efficiency of the planting implement, and that a long tongue assembly is desirable to accommodate pivotal and scissors-type implement folding configurations, the industry has developed telescoping tongue assemblies driven by large hydraulic cylinders to extend and accommodate implement transport, and to retract and provide a minimal turning radius during operation.
However, the above-described agricultural implement has drawbacks. Methods that include extending and retracting the large hydraulic cylinders needed to manipulate a telescoping tongue assembly are costly to manufacture and operate. Also, extending and retracting large hydraulic cylinders requires a significant amount of hydraulic oil, which makes the process of extending and retracting the tongue assembly more time consuming. Therefore, there is a need or desire for an enhanced brake system for an agricultural implement that is less costly to manufacture, operate, and that reduces transition time in accommodating the implement between transport and operation in the field. The brake system should also be configured to be utilized with a wide variety of implements or trailers towed behind a tow vehicle, in addition to those related to agriculture.